This invention relates to joists, and specifically to a hanger which supports an I-beam joist.
A great variety of metallic hangers are known which are used to secure wooden structural members to one another. The hangers generally include a lip or tab which rests on top of a support and some type of structure for connecting the tab to a joist. In some instances, a saddle arrangement is provided where a transverse support extends across the bottom of the joist being supported. Other forms of hangers rely on fasteners, such as nails, to retain the joist in position relative to the hanger and the support element.
One of the drawbacks with existing hangers is their reliance on fasteners such as nails to secure the joist in the hanger. The driving of a nail into a piece of wood is a stressinducing event which may ultimately decrease the life expectancy of the structural element. Another problem associated with known hangers relates to the positioning of joists relative to supports and hangers. In some instances, the hanger may be improperly positioned on the joist or beam, resulting in misalignment of the two elements. One form of device which attempts to overcome this alignment problem is disclosed in U.S. Pat. No. 4,411,548 to Tschan. In the Tschan patent, a base or seat is provided to support the bottom of the joist while a top flange is provided to retain the hanger and joist on the support. A drawback with the Tschan joist hanger, and with many other conventional systems, is that a different size hanger must be used for each size of joist, resulting in the requirement to stock a great variety of hanger sizes.
A problem with some other prior art hangers is that the hanger is as long as the beam is deep, thus dramatically increasing the cost of the hanger system. Conventional hanger systems may also involve a different type of hanger at the top and bottom of the beam if the beam or joist is connected at a sloped angle; that is, if the upper portion of the beam is connected using a bracket defining an acute angle, a bracket defining a corresponding obtuse angle must be used at the bottom. Yet another drawback with existing systems is that many hangers do little to prevent buckling of the web which extends between the chords of an I-beam.
It is therefore an object of the present invention to overcome the drawbacks and limitations of the prior art proposals. More specifically, the invention has the following objects:
(1) to provide a hanger which may be used with I-beams of virtually any depth or slope;
(2) to develop a hanger which may be used with conventional I-beams by adding blocks to the webs thereof;
(3) the provision of a hanger which allows some lateral adjustment of an I-beam relative to a support for the beam;
(4) to provide a hanger which is self indexing with the top of the beam and which therefore indexes the top of the beam to a support;
(5) to develop a hanger which is easily and inexpensively fabricated and which has a high degree of structural integrity; and
(6) the provision of an I-beam joist system which is stronger than existing systems but which can be easily assembled by workers having little expertise or training, and without having to use special equipment.